In recent years, field emission devices have attracted much attention due to the advantages, such as low operating voltage, low power consumption, no deflection coil, no X-ray radiation, radiation resistance and magnetic interference resistance, etc. By exciting the luminescent material using field emission cathode ray, field emission light source of high luminance and good color rendering properties can be obtained, which can be applied to professional lighting, display, instructions, general lighting and other fields.
Preparation of fluorescent powders of great performance is a key to prepare field emission devices of excellent performance. At present, fluorescent materials provided in field emission devices are commonly luminescent materials of traditional cathode-ray tube and projection television kinescope, such as sulfide series, oxide series and oxysulfide series fluorescent powders. For example, Xiong Liangming et al., CN Patent. No. 200410025310.5 discloses a method for preparing green powders of zinc silicate doped with manganese ions by means of low-temperature solid phase reaction. Mesoporous silica, zinc salt and manganese salt in the +2 valence state are provided and used as raw materials, weigh accurately mesoporous silica and disperse in alcoholic solutions of zinc salt and manganese salt in the +2 valence state, after drying, under the protection of neutral gas, calcine at 750° C. to 950° C. to prepare green powders of zinc silicate doped with manganese ions of high efficiency by means of solid phase reaction. The green powders of zinc silicate doped with manganese ions prepared by such method are good in color purity, but low in luminous efficiency.